﻿// This software is part of the Autofac IoC container
// Copyright © 2011 Autofac Contributors
// http://autofac.org
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

namespace Autofac.Core.Resolving
{
    class CircularDependencyDetector
    {
        /// <summary>
        /// Catch circular dependencies that are triggered by post-resolve processing (e.g. 'OnActivated')
        /// </summary>
        const int MaxResolveDepth = 50;

        static string CreateDependencyGraphTo(IComponentRegistration registration, IEnumerable<InstanceLookup> activationStack)
        {
            if (registration == null) throw new ArgumentNullException("registration");
            if (activationStack == null) throw new ArgumentNullException("activationStack");

            var dependencyGraph = Display(registration);

            foreach (var requestor in activationStack.Select(a => a.ComponentRegistration))
                dependencyGraph = Display(requestor) + " -> " + dependencyGraph;

            return dependencyGraph;
        }

        static string Display(IComponentRegistration registration)
        {
            return registration.Activator.LimitType.FullName ?? string.Empty;
        }

        public static void CheckForCircularDependency(IComponentRegistration registration, Stack<InstanceLookup> activationStack, int callDepth)
        {
            if (registration == null) throw new ArgumentNullException("registration");
            if (activationStack == null) throw new ArgumentNullException("activationStack");

            if (callDepth > MaxResolveDepth)
                throw new DependencyResolutionException(string.Format(CultureInfo.CurrentCulture,
                    CircularDependencyDetectorResources.MaxDepthExceeded, registration));

            if (IsCircularDependency(registration, activationStack))
                throw new DependencyResolutionException(string.Format(CultureInfo.CurrentCulture,
                    CircularDependencyDetectorResources.CircularDependency, CreateDependencyGraphTo(registration, activationStack)));
        }

        static bool IsCircularDependency(IComponentRegistration registration, IEnumerable<InstanceLookup> activationStack)
        {
            return activationStack.Any(a => a.ComponentRegistration == registration);
        }
    }
}
